Regular physical exercise is associated with lower coronary heart disease (CHD) mortality, favorably affects coronary risk factors and increases cardiovascular functional capacity. However, fewer than one-third of Americans engage in regular physical exercise and even fewer over age 45 do so (20% of men, 10% of women). This is largely cause effective strategies for increasing the adoption and maintenance of the exercise habit in a broadly representative segment of Americans have not been developed. Research into these behavioral issues has been impeded by 1) the need for direct supervision of high intensity group programs to validate adherence to exercise training and produce training changes in a relatively short time, and 2) the lack of reliable methods for measuring adherence to training in the natural environment. The research proposed here extends previous research from our laboratory in which these obstacles were overcome: at-home exercise training at several levels of intensity augmented functional capacity significantly and close adherence was validated by solid-state recording devices and exercise logs. The proposed research integrates physiological, biochemical and behavioral aspects of exercise training. A randomized controlled trial is proposed in which 200 men and 200 postmenopausal women aged 45-64 who are found by means of a community survey of 3600 households to have an increased risk for CHD will be randomized to a control group or to one of three regimens of exercise training for the first year: moderate intensity or high intensity individual-monitored or high intensity supervised exercise. Training regimens will emphasize monitoring of performance, periodic feedback and relapse prevention. Outcome variables, measured over 2 years include plasma lipids, lipoproteins, apoproteins, lipase activity, glucose and insulin: sex hormones; cardiovascular reactivity to psychological stress; cigarette smoking; nutrient intake; psychological status and cardiovascular functional capacity. The proposed research addresses 3 important issues which influence the likelihood that physical exercise will be adopted by a substantial proportion of Americans: 1) What biochemical and physiologic effects are observed when exercise training is undertaken by a broadly representative segment of the population at increased risk for CHD, 2) what strategies are most effective in facilitating the adoption and maintenance of physical exercise by free-living individuals and 3) what are the most reliable means for documenting adherence to exercise training in these individuals?